SAN FRANCISCO (AP) — Chevron Corp. failed to maintain equipment at a California refinery and has not responded adequately to multiple airborne chemical releases, the U.S. Environmental Protection Agency said Tuesday.

The EPA filed a formal notice against Chevron finding 62 violations of federal environmental laws after an investigation spurred by the Aug. 6, 2012, fire.

Federal chemical safety investigators have determined the blaze was caused by the failure of a corroded, 1970s-era pipe that released a massive gas cloud and sent thousands of people to hospitals seeking medical attention.

The EPA called Chevron’s risk management at the Richmond facility a “pervasive failure” and warned it could pursue criminal charges or fines if the company fails to address the violations.

Chevron spokeswoman Melissa Ritchie said the company is working with the EPA and other agencies to remedy issues identified in investigations by the government and the company.

“In Richmond, a full, comprehensive inspection of the refinery is ongoing,” Ritchie said. “To date, we have inspected thousands of individual piping components and are replacing them as necessary based on the results of these inspections.”

Jared Blumenfeld, the EPA’s regional administrator, said investigators determined Chevron’s culture does not place high enough emphasis on safety. He said the company failed to verify that its own risk management plan was being used by refinery staff.

“The reward system is focused on the number of running hours of the facilities, and how that affected bonuses and performance,” Blumenfeld said. Chevron “needs to impose one where the risk management plan is put into everyone’s job.”

The EPA’s notice came a day after the U.S. Chemical Safety Board released its draft investigative report of the 2012 fire.

The board also found that Chevron had ignored its own safety recommendations related to the pipe that burst, and it urged California to adopt more active refinery oversight regulations to help reduce such accidents in the future.

The oil company has pleaded no contest to six charges related to the fire, including failing to correct deficiencies in equipment and failing to require the use of certain equipment to protect employees from potential harm. It agreed to $2 million in fines and restitution.

Also, in January the company said it paid about $10 million in connection with nearly 24,000 claims from residents and as compensation to area hospitals and local government agencies.

Company officials said most of that $10 million went to hospitals for medical exams and treatment immediately following the incident.